Development and validation of a high-performance thin-layer chromatographic method with densitometric detection for determination of bisacodyl in pharmaceutical tablets

A densitometric method has been developed for determination of the laxative bisacodyl in enteric-coated tablets on channeled, high-performance silica gel layers with pre-adsorbent region and containing a fluorescent indicator. After extraction of the analyte with ethanol the extracts and bisacodyl standards were spotted by use of a Linomat spray-on applicator and the plates developed with ethyl acetate–methanol–glacial acetic acid, 85:10:5, as mobile phase. Quantitative evaluation was performed by measuring the absorbance of the analyte zones at 254 nm in the reflectance mode. The method is shown to have the selectivity, accuracy, precision, and high sample throughput that make it useful for routine analysis of the pharmaceutical preparation in industry quality control and regulatory laboratories. An alternative extraction procedure and mobile phase are suggested for analysis of bisacodyl tablets with different formulations.